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		<H1><A name="_information_schema.referential_constraints"></A>REFERENTIAL_CONSTRAINTS</H1>
		<P>Contains one row for each foreign constraint in the current database. This 
			information schema view returns information about the objects to which the 
			current user has permissions. The <B>INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS </B>
			view is based on the <B>sysreferences</B>, <B>sysindexes</B>, and <B>sysobjects</B>
			system tables.</P>
		<P>To retrieve information from these views, specify the fully qualified name of <B>INFORMATION_SCHEMA</B><I>
				view_name</I>.</P>
		<TABLE id="Table1" cols="3" cellPadding="2" rules="all" width="587" border="1" frame="box">
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				<TH class="label" width="32%">
					Column name</TH>
				<TH class="label" width="23%">
					Data type</TH>
				<TH class="label" width="45%">
					Description</TH></TR>
			<TR vAlign="top">
				<TD width="32%"><B>CONSTRAINT_CATALOG</B></TD>
				<TD width="23%"><B>nvarchar(128)</B></TD>
				<TD width="45%">Constraint qualifier.</TD>
			</TR>
			<TR vAlign="top">
				<TD width="32%"><B>CONSTRAINT_SCHEMA</B></TD>
				<TD width="23%"><B>nvarchar(128)</B></TD>
				<TD width="45%">Constraint owner.</TD>
			</TR>
			<TR vAlign="top">
				<TD width="32%"><B>CONSTRAINT_NAME</B></TD>
				<TD width="23%"><B>sysname</B></TD>
				<TD width="45%">Constraint name.</TD>
			</TR>
			<TR vAlign="top">
				<TD width="32%"><B>UNIQUE_CONSTRAINT_CATALOG</B>
				</TD>
				<TD width="23%"><B>nvarchar(128)</B></TD>
				<TD width="45%">Unique constraint qualifier.</TD>
			</TR>
			<TR vAlign="top">
				<TD width="32%"><B>UNIQUE_CONSTRAINT_SCHEMA</B>
				</TD>
				<TD width="23%"><B>nvarchar(128)</B></TD>
				<TD width="45%">Unique constraint owner.</TD>
			</TR>
			<TR vAlign="top">
				<TD width="32%"><B>UNIQUE_CONSTRAINT_NAME</B>
				</TD>
				<TD width="23%"><B>sysname</B></TD>
				<TD width="45%">Unique constraint.</TD>
			</TR>
			<TR vAlign="top">
				<TD width="32%"><B>MATCH_OPTION</B></TD>
				<TD width="23%"><B>varchar(7)</B></TD>
				<TD width="45%">Referential constraint-matching conditions. Always returns NONE, 
					which means that no match is defined. The condition is considered a match if
					<UL type="disc">
						<LI>
							At least one value in the foreign key column is NULL;
							<P class="tl">Or
							</P>
						<LI>
							All values in the foreign key column are not NULL and there is a row in the 
							primary key table with exactly the same key.
						</LI>
					</UL>
				</TD>
			</TR>
			<TR vAlign="top">
				<TD width="32%"><B>UPDATE_RULE</B></TD>
				<TD width="23%"><B>varchar(9)</B></TD>
				<TD width="45%">The action that is taken if a Transact-SQL statement violates 
					referential integrity defined by this constraint.
					<P>Returns either NO ACTION or CASCADE. If NO ACTION is specified on ON UPDATE for 
						this constraint, then the update of the primary key referenced in the 
						constraint will not be propagated to the foreign key. If such update of a 
						primary key will cause a referential integrity violation because at least one 
						foreign key contains the same value, SQL Server will not execute any change to 
						the parent and referring tables. SQL Server also will raise an error.</P>
					<P>If CASCADE is specified on ON UPDATE for this constraint, then any change to the 
						primary key value is automatically propagated to the foreign key value.</P>
				</TD>
			</TR>
			<TR vAlign="top">
				<TD width="32%"><B>DELETE_RULE</B></TD>
				<TD width="23%"><B>varchar(9)</B></TD>
				<TD width="45%">The action that is taken if a Transact-SQL statement violates 
					referential integrity defined by this constraint.
					<P>Returns either NO ACTION or CASCADE. If NO ACTION is specified on ON DELETE for 
						this constraint, then the delete on the primary key referenced in the 
						constraint will not be propagated to the foreign key. If such delete of a 
						primary key will cause a referential integrity violation because at least one 
						foreign key contains the same value, SQL Server will not execute any change to 
						the parent and referring tables. SQL Server also will raise an error.</P>
					<P>If CASCADE is specified on ON DELETE on this constraint, then any change to the 
						primary key value is automatically propagated to the foreign key value.</P>
			</TR>
		</TABLE>
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